Optical fiber waveguides are rapidly proliferating throughout the entirety of terrestrial based voice and data communications systems. Individual optical fibers are typically long cylindrical structures, usually having a circular cross section. In its simplest form, an optical fiber typically has two coaxial regions, a central light-guiding core and a surrounding cladding. Both are typically formed of glass fiber, although the cladding may be of other suitable material, such as plastic having a lower index of refraction than the glass core. The core may range from five to 100 microns in diameter, while the outside cladding diameter may range from 8 to 140 microns. A sheath or buffer of a different material typically surrounds the waveguide to provide optical isolation with adjacent fibers and to provide mechanical protection for the delicate, extremely small fiber waveguide. Optical fiber waveguides are typically collected together in a cable having an impervious, reinforced outer skin.
While optical fiber waveguides have been conventionally collected into cables, a need has remained for effective apparatus and methods for handling the fiber waveguides at terminal ends, such as at long distance network, outside plant or service subscriber interfaces.
It is well known that individual optical fibers are extremely small, fragile and difficult to handle, particularly in connection with splicing and in the installation of optical taps. Specialized tooling and techniques have been proposed in the prior art for handling and aligning the delicate, minute fiber waveguides for such purposes as splicing and attachment of connectors.
U.S. Pat. Nos. 4,537,466 and 4,623,156, the disclosures of which are incorporated herein by reference, describe optical fiber chucks for precise fiber positioning. U.S. Pat. No. 4,728,169, the disclosure of which is hereby incorporated by reference, describes a passive tap and fiber positioning. U.S. Pat. Nos. 4,498,732 and 4,478,486 discuss fiber organization and storage methods to prevent bending. U.S. Pat. No. 4,160,580 describes a device for terminating the end of an optical fiber with a connector. An article by Evans et al. entitled "Optical Fiber Alignment Tool" appearing in IBM Technical Disclosure Bulletin Vol. 22, No. 2, July 1979, pages 686-687 describes a precise Vee groove formed in the bed of a tool for aligning and holding the ends of optical fiber waveguides together for laboratory activities. Vees of soft elastomer deformably press against sections adjacent to the ends, and thereby urge the fibers into desired axial registration and alignment.
While these specialized devices have been disclosed, one unsolved problem has been to provide an effective fiber handling device and method for field use by ordinarily skilled craftsmen and installers which is repeatable, which efficiently couples a light/electricity translation element to the optical fiber waveguide, and which protects and minimizes the potential for physical damage to the optical fiber.
It has been discovered that if an optical fiber waveguide is subjected to bending, it is possible to inject light energy into the fiber waveguide or withdraw light energy from the fiber waveguide at the situs of the bend. Bends formed in optical fiber waveguides for the intended purposes of light injection or withdrawal are known as optical couplers or "taps"; and, when a coupling body having a matched index of refraction is disposed adjacent to the fiber and to a photodetector or light source, light withdrawal or injection may respectively be usefully carried out without need for invasion of the cladding material. Examples of optical fiber taps are to be found in U.S. Pat. Nos. 4,664,732; 4,586,783; 4,557,550 and 4,270,839. A particularly preferred tap is described in U.S. patent application Ser. No. 07/213,642, filed on June 30, 1988 (now abandoned), which is assigned to the assignee of the present invention. The disclosures of U.S. Pat. Nos. 4,664,732; 4,586,783 and U.S. patent application Ser. No. 07/213,642 (now abandoned), are incorporated herein by reference.